textproduct: Albany

WHAT HAS CHANGED

A Severe Thunderstorm Watch has been issued for all of eastern New York and Litchfield, Berkshire, and Bennington counties in western New England until 9 PM tonight.

Wind gusts have been increased through this afternoon as breezy conditions continue outside of thunderstorm activity.

A Flood Watch continues through 11 PM tonight for Dutchess and Ulster counties for the potential for flash flooding due to excessive rainfall from thunderstorms.

KEY MESSAGES

1) Scattered to numerous thunderstorms continues through this evening across all of eastern New York and western New England. Some could be severe, with the potential for damaging wind gusts.

2) Thunderstorms this afternoon and evening will be capable of producing heavy downpours, which could result in flooding of urban and low lying areas, especially across Ulster and Dutchess counties.

3) A few lingering rain showers or thunderstorms will continue into Friday for southern and eastern areas, but no additional severe storms or flooding is expected. Seasonable and dry weather is expected over the weekend.

DISCUSSION

KEY MESSAGE 1...

Afternoon Update: A Slight Risk (level 2 of 5) for severe thunderstorms continues through the early evening hours as latest radar scans and visible satellite imagery continues to show numerous showers and thunderstorms developing. See previous discussion below for more details.

Previous Discussion: An upper level disturbance is currently located over the Upper Great Lakes and it will be lifting across southern Ontario and into western Quebec for today. At the surface, a cold front is located well west of the area over the Ohio Valley and Midwest. Surface warm front will be lifting across the area this morning and a surface trough ahead of the main front will be approaching the area for this afternoon into this evening. This will be the focus for showers and thunderstorms, which look to develop by the early to mid afternoon hours.

There looks to be sufficient shear and instability for organized storms today. The 00z HRRR and 00z SPC HREF both shows instability should reach the 1000-2000 J/kg range, especially for southern areas. 0-6 km bulk shear should be around 30 kts today. As a result, storms look to organize into small bows or lines by late this afternoon into this evening, bringing a threat for straight-line wind damage. Some the stronger storms could contain some hail as well. An isolated tornado is possible for any supercells ahead of the main line and the 00z HRRR does suggest there may be enough low-level helicity, although Sig Tor parameters looks to max out around 1-2 today, mainly for eastern areas. AI/ML guidance continues to show the potential for damaging winds and an isolated tornado across the region for today as well and has been showing this signal for the past few days. SPC has expanded the Slight Risk (Level 2 of 5) and it now is in place for nearly the entire ALY Forecast area.

Storms may linger into the evening, but will start to diminish between 8 PM and 10 PM, as the best forcing shifts eastward and the loss of daytime heating allows instability to wane.

KEY MESSAGE 2...

Afternoon Update: The Slight Risk (level 2 of 4) has been expanded for this afternoon and evening to include almost all of eastern NY and western New England as the environment is favorable for thunderstorms to produce heavy rainfall. See previous discussion below for more details.

Previous Discussion: In addition to the severe threat, there will be the potential for heavy rainfall and localized flooding this afternoon into this evening. PWAT values will be surging to 1.50 to 2.00 inches for this afternoon and evening thanks to the low-level southerly flow in place. Dewpoints will be reaching well into the 60s to near 70 by late this afternoon, so there will be plenty of moisture available. Rainfall rates can easily reach 1-2 inches per hour in this type of environment.

CAMs suggests that several rounds of storms are possible and some areas may see training of precipitation. Some of the CAMs (especially the RRFS) suggests that localized rainfall totals may exceed 4 inches. While the placement has varied somewhat from run-to-run, the consensus in ensembles seems to suggest that southern areas (Ulster and Dutchess Counties) may have the highest potential for heavy rainfall, as cellular activity may occur in addition to a main line of storms. As a result, have issued a Flood Watch for the potential for flash flooding for Ulster and Dutchess Counties, which also matches up with the Slight Risk (Level 2 of 4) for Excessive Rainfall from WPC. Urban and low lying areas would be the most susceptible to flooding, which may result in damaged and impassable roadways. As always, travelers are reminder to need cross flooded roadways.

In addition to southern areas, other parts of the area may still see flooding rainfall and some guidance does suggest parts of the Lake George Region and southern VT could see repeated downpours as well, so will need to monitor trends and possibly expand the current Watch further north.

KEY MESSAGE 3...

Afternoon Update: No changes to the current forecast. See previous discussion below for more details.

The storm's main cold front will be crossing on Friday. A few additional showers or thunderstorms are possible on Friday, mainly for southern and eastern areas, but coverage will be lower than Thursday. There won't be as much instability and shear, so storms won't be able to become severe and probably won't be widespread enough to cause any additional flooding. The threat for additional precipitation will end from west to east during the afternoon hours with the passage of the cold front.

Over the weekend, high pressure will allow for dry weather and seasonable conditions. Plenty of sunshine is expected on Saturday with highs in valley areas in the upper 70s to low 80s. Dewpoints will be more comfortable compared to recent days, with values in the 50s to low 60s. It will turn slightly more humid and warmer on Sunday, but it looks to stay dry with a partly sunny sky and highs reaching the lower to middle 80s.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Through 18z/Friday...VFR conditions will start to deteriorate over the next few hours as an approaching cold front brings showers and scattered thunderstorms this afternoon. Current KENX radar and satellite imagery shows some showers already entering the region as well as some low level stratus. Model guidance shows the best chance for thunderstorms to develop between about 18z and 24 across all the terminals resulting in lowered flight conditions to MVFR/IFR, if any develop over the terminals. A break in the showers and thunderstorms could occur around 00z however cigs are expected to still remain MVFR. Due to the ample low level moisture and low T/TD spread, fog/mist could develop across all the terminals, with model soundings suggesting KGFL and KPSF to have the best chance of IFR/LIFR flight conditions. Confidence is low at this time that any lingering showers and/or thunderstorms will pass over the terminals in the early morning hours before sunrise but the possibility is mentioned in a PROB30 for KGFL, KALB, and KPOU. Any fog and showers should dissipate with sunrise, however pesky low stratus is expected to persist through the end of the TAF period across all sites, with KPSF likely remaining MVFR through the end of the TAF period.

Winds this afternoon will be out of the south/southwest 10-15 kt with gusts up to 25 kt and gusts near 35 kt where any thunderstorms develop. Tonight winds become light and/or calm before increasing after sunrise with speeds 5-10 kt out of the southwest at KGFL, KPOU, and KPSF and out of the northwest at KALB.

Outlook...

Friday Night: No Operational Impact. NO SIG WX. Saturday: No Operational Impact. NO SIG WX. Saturday Night: No Operational Impact. NO SIG WX. Sunday: No Operational Impact. NO SIG WX. Sunday Night: Moderate Operational Impact. Chance of SHRA. Monday: Moderate Operational Impact. Chance of SHRA...TSRA. Monday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Tuesday: Moderate Operational Impact. Chance of SHRA...TSRA

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...Flood Watch until 11 PM EDT this evening for NYZ063>066. MA...None. VT...None.